THERMOANALYTICAL STUDIES OF INTUMESCENT SYSTEMS

Fire retardant intumescent coatings which produce a swollen char on he ating are being frequently used to protect buildings containing struct ural steel from the effects of exposure to high temperatures caused by fire. This paper contains details of a study carried out using therma l analysis techniques to elucidate the mechanisms of the development o f intumescent chars during the heating of an intumescent coating syste m based on ammonium polyphosphate, pentaerythritol and melamine. In pa rticular, the role of melamine as the spumific agent has been studied. The melamine is shown to react chemically with the ammonium polyphosp hate in addition to carrying out its role as the spumific, or blowing agent.